Management of svt in adult

SVT MANAGEMENT GUIDELINE IN ADULTS

1. ACC/AHA GUIDELINE FOR MANAGEMENT OF SVT IN ADULT PATIENTS DR MAHENDRA CARDIOLOGY,JIPMER

2. SVT tachycardia's having atrial and/or ventricular rates in excess of 100 bpm at rest. mechanism of which involves tissue from the His bundle or above. SVTs include- inappropriate sinus tachycardia AT (including focal and multifocal AT ) macro reentrant AT junctional tachycardia AVNRT , and various forms of accessory pathway-mediated reentrant tachycardias . In this guideline, the term does not include AF.

3. prevalence of SVT is 2.25 per 1,000 . incidence of PSVT is 36 per 100,000 persons per year . Women have twice the risk of men of developing PSVT . Individuals >65 years of age have >5 times the risk of younger persons of developing PSVT.

4. Clinical History Modes of presentation- documented SVT in 38 % palpitations in 22 % chest pain in 5 % syncope in 4 % AF in 0.4 % sudden cardiac death in 0.2%

5. Algorithm for Short term management of SVT

6. Differential diagnosis with adenosine

7. SPECIFIC TACHYARRHYTHMIAS

8. Sinus Tachyarrhythmias - Physiological Sinus Tachycardia Inappropriate Sinus Tachycardia Sinus Node Re-Entry Tachycardia

9. Inappropriate Sinus Tachycardia persistent increase in resting heart rate unrelated to the level of physical, emotional, pathological,or pharmacologic stress. 1 . Enhanced automaticity of the sinus node 2. Abnormal autonomic regulation of the sinus node with excess sympathetic and reduced parasympathetic tone . Diagnosis- presence of a persistent sinus tachycardia ( heart rate more than 100 bpm) during the day with excessive rate increase in response to activity and nocturnal normalization of rate as confirmed by a 24-hour Holter recording. tachycardia (and symptoms) is nonparoxysmal . P-wave morphology and endocardial activation identical to sinus rhythm. Exclusion of a secondary systemic cause.

10. Sinus Node Re-Entry Tachycardia Diagnosis- tachycardia and symptoms are paroxysmal. microreentrant circuit P-wave is identical to sinus rhythm. distinguish sinus node reentry from sinus tachycardia are an abrupt onset and termination often a longer RP interval than that observed during normal sinus rhythm. t ermination occurs with vagal maneuvers or adenosine. Induction of the arrhythmia is independent of atrial or AV-nodal conduction time.

11. Treatment- no controlled trials of drug prophylaxis for pts with SNRT. respond to vagal maneuvers, adenosine, amiodarone , beta blockers, nondihydropyridine calcium-channel blockers, or even digoxin . EP studies for frequent or poorly tolerated episodes of tachycardia that do not adequately respond to drug therapy. Radiofrequency catheter ablation is generally successful.

12. AVNRT Presence of a narrow complex tachycardia with regular R-R intervals and no visible p waves. P waves are retrograde and are inverted in leads II,III,avf . P waves are buried in the QRS complexes –simultaneous activation of atria and ventricles – most common presentation of AVNRT –66%. If not synchronous –pseudo s wave in inferior leads ,pseudo r’ wave in lead V1---30% cases .

13. Atypical AVNRT Arrows point to the P wave . The reentrant circuit involves anterograde conduction over a fast atrioventricular node pathway, followed by retrograde conduction in a slow atrioventricular node pathway, resulting in a retrograde P wave (negative polarity in inferior leads) with long RP interval.

14. AVRT Typical – RP interval < PR interval RP interval > 80 milli sec Atypical –RP interval > PR interval Concealed bypass tract – only retrograde conduction Manifest bypass tract– both anterograde and retrograde. Electrical alternans –the amplitude of QRS complexes varies by 5 mm alternatively.

15. PRinterval RP interval PR interval

16. Orthodromic Atrioventricular Reentrant Tachycardia The reentrant circuit involves anterograde conduction over the atrioventricular node, followed by retrograde conduction over an accessory pathway, which results in a retrograde P wave with short RP interval.

17. Junctional Tachycardia

18. 1 . Junctional Tachycardia- origin from the AV node or His bundle heart rates of 110 to 250 bpm and a narrow complex or typical BBB conduction pattern Atrioventricular dissociation is often present arrhythmia is thought to be either abnormal automaticity or triggered activity. uncommon in adults typically seen in infants postoperatively, after cardiac surgery for congenital heart disease.

19. 2. Nonparoxysmal Junctional Tachycardia benign arrhythmia narrow complex tachycardia with rates of 70 to 120 bpm . enhanced automaticity arising from a high junctional focus or in response to a triggered mechanism cannot be terminated by pacing maneuvers . Cause- digitalis toxicity , postcardiac surgery hypokalemia , myocardial ischemia. chronic obstructive lung disease with hypoxia inflammatory myocarditis.

20. Focal AT and MAT

21. AT Rapid (usually <250 beats/ min), relatively regular rhythms that originate in the atrial musculature. Mechanisms include abnormal automaticity and triggered activity. Foci are most frequently found in the pulmonary veins in the LA and the crista terminalis in the right atrium. Myocardial infarction, nonischemic heart disease,obstructive lung disease, serum electrolyte disorders, and drug toxicity

22. RP intervals can be variable RP often > PR (Example slower than more common rate 150-250 beats per min) Atrial Tachycardia V1 Differs from AV nodal or AV reentrant SVT

23. MAT rapid, irregular rhythm with at least 3 distinct morphologies of P waves on the surface ECG distinct isoelectric period between P waves . The P-P, PR, and R-R intervals are variable. associated with pulmonary disease, pulmonary hypertension, coronary disease, and valvular heart disease , hypomagnesemia and theophylline therapy . first-line treatment is management of the underlying condition

24. Multifocal Atrial Tachycardia ECG Characteristics: Discrete P waves with at least 3different morphologies. Absence of one dominant atrial pacemaker Atrial rate > 100 bpm. The PP, PR, and RR intervals all vary.

25. Atrial Flutter Usually a single, irritable foci in the atria (right) AV node protects the ventricles by blocking some of the atrial impulses ( decremental conduction) P waves take on a “ sawtooth ” appearance and are called F waves or flutter waves Atrial rhythm and ventricular response are usually regular Atrial rate 250-350 beats/min. Ventricular rate varies depending on the number of impulses the AV node is blocking No P waves or PR interval QRS normal width or with aberrancy

26. Special population ADULT ACHD PREGNANCY OLDER POPULATION

27. ACHD SVT is observed in 10% to 20% of ACHD . increased risk of heart failure, stroke, and SCD. mechanism of SVT in ACHD patients is macro reentrant AT, which accounts for at least 75% of SVT

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